The invention relates to an hydraulic shock absorbing arrangement for pipe conduit systems.
One such shock absorbing arrangement is disclosed in German Offenlegungsschrift [Laid-open Application] No. 1,650,086. Its purpose is to cause the pipe conduit system to be unaffected by normal displacements, originating generally in thermal expansion, and it also acts as a rigid support in the event of rapid, or shock-like, displacements in the form of pipe thrusts, arising from earthquakes, or the like, so that, for instance, in nuclear power stations such pipe thrusts are not transmitted directly to the reactor with resultant damage, but can be dissipated outside the reactor, even if this were to result in damage to the pipe conduit system. For this purpose, there are provided throttle valve assemblies which close in the manner of non-return valves in the event of faster movements in the pipe conduit system, or of intensified flow effects in the pressure liquid caused by these.
In the known shock absorber arrangement, a pressure cylinder is concentrically housed in a supply and compensation container for the pressure liquid, in order to permit losses of the pressure liquid through leakage from a piston rod guide to be compensated. Such shock absorbing arrangements must have a long useful life, together with a high degree of functional safety. The throttling valve assemblies in the cylinder chambers on both sides of the piston are located substantially radially between the supply and compensation containers in the walls of the pressure cylinder. In addition, in the supply and compensation container there is provided a compensation bellows which, on the one hand, absorbs the volume changes arising from temperature fluctuations in the interior of the shock absorbing arrangement and, on the other, serves to compensate for volume changes originating in the differential volumes being displaced by the piston rod on the two sides of the piston as the piston moves.
The conventional shock absorbing arrangement solves the problem of providing a self-contained structural unit without exposed pipes which are subject to damage. However, due to the supply and compensation container surrounding the pressure cylinder, this structural unit is comparatively large and so occupies a comparatively large space, which creates difficulties in the mounting of the unit. Moreover, losses of the pressure liquid through leakage from the piston rod guide make it necessary to keep the arrangement under regular observation, which may necessitate occasional refilling of the supply and compensation container with fresh pressure liquid. This work is expensive and, in the case of nuclear power stations, must be carried out in a highly responsible manner since if it is neglected or carried out in a careless manner, the consequences can be catastrophic.